Power supply for magnetic core devices



Oct. 27, 1964 G. WILEY POWER SUPPLY FOR MAGNETIC CORE DEVICES Filed June 5, 1961 INVENTOR MMPE/ms Q W45) "when United States Patent 3,154,693 POWER SUPPLY FOR MAGNETIC CSRE DEVTCES Lawrence G. Wiiey, (lamp Hiil, Harrisburg, Pa., assignnr to AlVIP Incorperated, Harrisburg, Pa, a corporation of New Jersey Filed June 5, 1961, Ser. No. 114,695 11 Claims. (Cl. Sin-88.5)

This invention relates to an improved power supply for magnetic core shift registers and the like.

An object of this invention is to provide an improved power supply for operating magnetic core devices, such as shift registers, at high speeds.

Another object is to provide such a power supply which is very reliable, which is easy to control, and which is relatively simple and inexpensive.

A more specific object is to provide a power supply for energizing at high speed a magnetic core shift register using multi-aperture cores.

These and other objects will in part be understood from and in part pointed out in the description given hereinafter.

In a multi-aperture (MD) core shift register, such as shown in U.S. Serial No. 9282, now U.S. Patent No. 2,995,731, transfer of information from one core in the register to the next is accomplished by driving the one core with a properly shaped advance current which returns the core to clear condition and simultaneously causes the transfer of the information stored in this core to the next core. Thereafter, the latter core is cleared by a second advance current, and so on. Between the advance currents applied to the cores there is also applied a prime current which, so to speak, conditions each given core in the register so that thereafter upon the occurrence of an advance current, information can be transferred to the next core. The construction and operation of such a shift register is explained in detail in the aforesaid patent application.

Now, one of the problems with a shift register of this kind is how to apply to the various cores currents of proper amplitude and shape to effect the required shifting operation. This problem becomes particularly diflicult at very high speeds of operation, for example, kilocycles. The present invention provides an improved drive current supply unit particularly suitable for a magnetic core device of this kind. This new driver unit can be operated at high speed, but yet it uses only solid state devices (i.e. no vacuum tubes); it is extremely reliable in operation.

In accordance with the present invention in one specific embodiment thereof, a single capacitor is arranged to be charged from a battery through one advance winding of a shift register, such as described above. The changing of the capacitor is controlled on command by a solid state four-layer diode which functions as a high speed switch. This charging of the capacitor serves to provide a properly shaped advance current for one group of the cores in the register. Thereafter, the charge which has accumulated in the capacitor is discharged on command through a similar four-layer diode switch through the other advance winding of the shift register. The cores of the register during and between the advance currents are supplied by a continuous prime current which does not interfere with the advance currents and which nonetheless provides the necessary priming of the cores. This cycle of charging and discharging of the capacitor to provide the advance currents can be carried out at high speed, and since the second advance current depends upon the first, a high degree of fail-safe operation is achieved. As will appear, this new driver can be controlled by a square-wave voltage, which is easily obtained. Moreover, the parts required for this new driver are relatively few and inexpensive.

Ice

A better understanding of the invention together with a fuller appreciation of its many advantages will best be gained from the following description given in connection with the single figure of the accompanying drawing which is a schematic circuit of a power supply embodying features of the invention.

The power supply 19 shown in the drawing is connected in circuit with a shift register, generally indicated at 12. This register, which can be identical to the one described in the aforesaid patent application, includes a prime winding 14, a first advance winding 16, and a second advance winding 18, the prime winding being connected between each of the advance windings and ground.

Connected externally at the right to the junction of the prime and advance windings is a branch of the circuit for supplying a direct priming current to prime winding 14. This includes an isolating inductor 20, a resistor 22 and a battery 24 of suitable voltage. The direct current supplied from battery 24 is set and left at a value, for example, of ma.

Advance winding 16 is adapted to be energized with a properly shaped pulse of current which flows from the left through the winding and through prime winding 14 to ground. To this end the left end of advance winding 16 is connected to a blocking diode 353, a low ohmage, pulse shaping resistor 32, and a storage capacitor 34. The latter, as mentioned in the beginning, is adapted to be charged on command from a suitable voltage source, and in so doing to supply a properly shaped advance current pulse to advance winding 16. The left end of capacitor 34 is connected through a pulse shaping inductor 36, a blocking diode 38, and a four-layer diode 48 to the positive side of a battery 42. The latter is shunted by a large filter capacitor 44.

Now, the voltage from battery 42 is siightly less than enough by itself to break down diode 4t and cause it to conduct. Therefore, to cause this diode to turn on, there is applied to its upper electrode through an input capacitor 46 a suitable negative trigger voltage. This voltage may simply be a square wave of about 25 volts, peak-to-peak, and is easily obtained from a source (not shown). To keep the common junction of capacitor 46 and diodes 38 and 40 from floating with respect to direct voltage, a relatively high ohmage resistor 48 is connected from this point to ground.

Assuming that storage capacitor 34 is uncharged, when four-layer diode 4% is caused to conduct, as explained above, the capacitor begins to charge from battery 42. Inductor 36 and the inductance of windings 16 and 14 in series, and the resistance of resistor 32 are such in relation to capacitor 34 that the latter charges to the voltage of battery 42, the charging circuit being a damped resonant one.

With the charging of capacitor 34 an advance pulse is applied to winding 16. Thereafter, the capacitor is in the charged state, and this charge in turn is used for the advance current pulse applied to advance winding 18. When the voltage on capacitor 34 charges to approximately the voltage of battery 42, the potential across fourlayer diode 4% drops effectively to zero. This condition, since it is maintained for a brief instant, causes the diode to become non-conducting and to remain so even though the voltage across this diode during the following cycle of operation of circuit 10 again rises to the voltage of battery 42. This automatic extinguishing of the four-layer diode is an important operating feature of the circuit.

Once it is charged in order to discharge capacitor 34 into advance winding 18, there is connected to the left end of the capacitor a pulse-shaping inductor 59, a blocking diode 52, and a four-layer diode 54, the latter being connected to winding 18. To cause four-layer diode 54 to break down and conduct, there is applied to its junction 2 with diode 52 through a capacitor 56 a positive trigger voltage. This voltage may be simply the positive peaks of the square wave voltage also applied to capacitor 46 and four-layer diode 40.

When four-layer diode 54 conducts, the charge previously accumulated in capacitor 3 5 flows through advance winding 18, prime winding 14, and thence through a ground connection back through a diode 53 and a low ohmage resistor 64 to the right side of capacitor 34. The circuit formed by inductor S0, windings 1.3 and 14, re sister 64), and capacitor 34, is a damped resonant one so that a pulse of current, substantially identical to that which flowed through advance winding 16, now flows through advance winding 18. This pulse or" current leaves capacitor 34 uncharged, and as explained above the circuit is now ready to supply another drive pulse to winding 16 when the next negative cycle of the square wave applied to four-layer diode dtl occurs. The above described accumulation and the dissipation of each charge on capacitor 34 results in good power efficiency for the circuit, and also it prevents improper sequencing of the advance currents.

The function of diode 3i) is to block current flow to the left upon the discharge of capacitor 34, whereas diode 58 blocks current flow to ground, instead of through advance winding 16 during the charging of capacitor 34. The maximum rate at which drive pulses can be supplied by circuit 19 to windings i6 and 18 is determined here primarily by the recovery time of the four-layer diodes, which is of the order of a few microseconds.

In a power supply substantially identical to the supply in circuit 1!) which has been built and successfully operated, the four-layer diodes 46 and 54 were type 4AD50; the voltage of battery 42 was 35 volts; and capacitor 34 was 0.15 microiarad.

The above description is intended in illustration and not in limitation of the invention. Various changes or modifications in the embodiment set forth may occur to those skilled in the art and these can be made without departing from the spirit or scope of the invention as set forth.

I claim:

1. A high speed power supply comprising an input adapted to be energized by a constant voltage, a first solid state switch and a pulse shaping current charging circuit, a second solid state switch and a pulse shaping current charging circuit, a first and a second output to which windings of a shift register and the like are adapted to be connected, and a storage capacitor, said capacitor being connected in current charging relation between said input and one of said outputs by said first circuit, and being connected in current discharging relation with said other output by said second circuit.

2. The supply in claim 1 wherein said first and second switches are four-layer diodes.

3. The supply in claim 1 wherein said first switch is turned on by a trigger voltage of one polarity and said second switch is turned on by a trigger voltage of the opposite polarity.

4. The supply in claim 1 wherein said first and second switches are adapted to be triggered on by external signals, said first switch being automatically turned off when the voltage on said capacitor reaches approximately said constant voltage, and said second switch being automatically turned ofi when the voltage on said capacitor reaches zero.

5. A power supply adapted to energize with short current pulses alternate ones of inductive windings of a magnetic core shift register and the like, said supply comprising an input adapted to be energized by a direct voltage, a storage capacitor, a first switch adapted to be triggered on by a voltage, first means including a blocking diode connecting said first switch and said capacitor to one of the windings in a resonant charging circuit, a second switch adapted to be triggered on by a voltage, and second means including a blocking diode connecting said second switch and said capacitor in a resonant discharging circuit to another of said windings.

6. The supply in claim 5 wherein said first switch is a four-layer diode connected to be triggered on by a negative voltage and said second switch is a four-layer diode connected to be triggered on by a positive voltage.

7. A high speed power supply for supplying short energizing pulses to at least two separate windings of a magnetic core circuit such as a shift register, said supply comprising an input adapted to be energized with direct voltage, a storage capacitor, pulse shaping means in circuit with said capacitor, first switch means to connect said capacitor in a charging circuit between said input and one of the windings of the magnetic core circuit, second switch means to connect said capacitor in a discharging circuit with a second one of the windings of the circuit, and mews to trigger said first and second switch means on by external signals of spaced duration, said first and second switch means being triggered on by opposite momentary signal voltages, and thereafter remain on until the voltage across each switch means decreases nearly to zero, said first and second switch means being automatically turned otf by the charging and discharging respectively of said capacitor.

8. The supply in claim 7 wherein said first and second switch means are each a four-layer diode.

9. A high speed power supply for supplying short energizing pulses to at least two separate windings of a magnetic core circuit such as a shift register, said supply comprising an input adapted to be energized with direct voltage, a storage capacitor, pulse shaping means in circuit with said capacitor, first switch means to connect said capacitor in a charging circuit between said input and one of the windings of the magnetic core circuit, second switch means to connect said capacitor in a discharging circuit with a second one of the windings of the circuit, means to trigger said first and second switch means on by external signals of spaced duration, a first blocking diode connected in series with a first side of said capacitor and said first switch means, a second blocking diode connected in series with the second side of said capacitor and said second switch means, and a third blocking diode connected in a return path from said second side of said capacitor to said first side.

10. The supply in claim 9 in further combination with three windings of a magnetic core circuit, all of said windings being connected to a common point, said supply having two outputs, two of said windings being connected respectively to said outputs, the third winding being connected in said return path with said third diode, and in a second return path with the input of said supply.

11. The supply in claim 10 in further combination with means to supply a prime current in oppositedirection to said'third winding.

References Cited in the file of this patent UNITED STATES PATENTS 1,605,252 Mallory Nov. 2, 1926 2,409,897 Rado Oct. 22, 1946 2,414,363 Dietert et al. Ian. 14, 194? 

1. A HIGH SPEED POWER SUPPLY COMPRISING AN INPUT ADAPTED TO BE ENERGIZED BY A CONSTANT VOLTAGE, A FIRST SOLID STATE SWITCH AND A PULSE SHAPING CURRENT CHARGING CIRCUIT, A SECOND SOLID STATE SWITCH AND A PULSE SHAPING CURRENT CHARGING CIRCUIT, A FIRST AND A SECOND OUTPUT TO WHICH WINDINGS OF A SHIFT REGISTER AND THE LIKE ARE ADAPTED TO BE CONNECTED, AND A STORAGE CAPACITOR, SAID CAPACITOR BEING CONNECTED IN CURRENT CHARGING RELATION BETWEEN SAID INPUT AND ONE OF SAID OUTPUTS BY SAID FIRST CIRCUIT, AND BEING CONNECTED IN CURRENT DISCHARGING RELATION WITH SAID OTHER OUTPUT BY SAID SECOND CIRCUIT. 